This invention relates to a platen for a strip-up microfiche. In one of its more particular aspects this invention concerns a platen which is equipped with releasable holders for maintaining a strip-up microfiche in a substantially planar configuration.
Microfilm is being used today to an ever increasing extent as the information explosion makes the retention of records a formidable problem. Microfilm records can be stored in a fraction of the space required by originals and are therefore used to take optimum advantage of the storage space available.
Various microfilm formats are available including roll film, microcards and microfiche. Microfiche usage involves copying records upon an integral sheet of microfilm which contains a plurality of information-containing frames, sometimes as many as over one hundred, arranged in columns and rows. It is sometimes desirable, for the purpose of updating records, for example, to be able to change a part of the microfiche, for example a single frame thereof, without having to produce a completely new microfiche. For this purpose a variation of microfiche popularly known as a strip-up microfiche is used. In order to make a change in this type of microfiche, which consists of strips of microfilm, corresponding in number to the number of rows in the microfiche, which are adhered to each of two perforated edge strips, it is necessary only to remove the one strip which is to be changed and to replace it with a strip containing the updated or otherwise corrected information.
In use microfilm records, as in the case of other record storage media, must frequently be reproduced. Machines for duplicating microfiche are equipped with optical systems which expose a film, such as a diazo film, in order to produce thereon an image corresponding to the microfiche to be duplicated. In order to obtain a duplicate which is an accurate reproduction of the original microfiche, it is necessary that the positioning of the original be carefully controlled. The microfiche must be accurately placed in the optical path of the machine with the angular disposition of the original with respect to the optical path being such that no distortion is introduced into the duplicate. In the case of strip-up microfiche in particular it is essential that a planar configuration of the original microfiche be maintained. Since, however, the strip-up microfiche tends to bow at the middle it has been found necessary to devise means to hold the microfiche flat during the duplicating process. The systems heretofore devised tend to be somewhat unsatisfactory principally because they are less than one hundred percent effective or have proved to be cumbersome.